Expert calls for earthquake preparedness for Karachi, says city lies near triple plate junction and multiple fault lines
A magnitude 5.2 earthquake that struck Karachi on Tuesday evening occurred in the Sonmiani area of Hub district, where three tectonic plates – the Arabian plate, the Eurasian plate and the Indian plate – meet. This fact necessitates precautions on the part of Karachi residents.
Tectonic plates are massive, irregularly shaped sheets of solid rock that make up the Earth’s lithosphere – crust and upper mantle – and slowly move over the asthenosphere – semi-molten rock beneath them – driven by internal heat.
Speaking to The Express Pakinomist, National Seismic Center Director Ameer Haider Laghari said the earthquake was caused by a movement in the Arabian plate at the junction.
Read: 5.2 magnitude earthquake reported in Karachi
“As a result, tremors and vibrations were felt in many areas of Karachi. Fortunately, the intensity and depth of the earthquake was low,” he said, adding that the place near Sonmiani where the earthquake occurred also has no human settlement.
According to Laghari, it was not the first time an earthquake of this magnitude – slightly higher on the Richter scale than previous tremors – had been recorded.
However, he cautioned that this does not mean people should become completely complacent. Earlier, an earthquake with a magnitude of 5.0 was also recorded in 2020.
He said that the fault lines and tectonic boundaries near Karachi are mostly located at shallow depths where very high intensity earthquakes have never been recorded.
A fault line is a break or zone of fracture in the earth’s crust where blocks of rock move relative to each other and release stress as earthquakes or slowly through creep.
Karachi sits near several active fault lines, including the local Landhi Fault, Malir Fault and the nearby Hub Fault – influenced by the tectonic boundary of the Arabian, Indian and Eurasian plates.
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Experts identify around five active fault lines nearby, with recent minor tremors often releasing energy along the Landhi-Korangi fault.
Laghari stressed that whether an earthquake occurs at sea in the form of a tsunami or on land, basic preparedness training is extremely important and earthquake-resistant construction is equally important and requires special focus.
According to him, a micro-level survey regarding earthquakes in Karachi has also been conducted during the current year. “During this survey, a number of earthquakes were recorded on the Richter scale, although people could not feel them due to their low intensity,” he said.
The expert said that earthquakes were also recorded here in the 18th and 19th centuries; however, modern instruments were not available at the time, so their intensity was not recorded
In the past, there were forests and orchards along the fault lines, but now large areas are densely populated — a fact that Laghari said needs to be kept in mind while making plans to prevent earthquake-related incidents.
He pointed out that people in Japan also live near fault lines, but their building practices take this natural process into account.
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“There is a need to formulate a proper policy to ensure that construction near fault lines is earthquake resistant or that construction and civil works meet standards capable of withstanding earthquakes,” he said.
In the middle of the current year, 57 earthquakes were recorded over a period of 23 days along the Korangi-Landhi fault line, whereas in 2009, approximately 36 earthquakes were recorded over a period of four months.
